Question: $ { \left[\begin{array}{rrr}{-1} & {2} & {3} \\ {-1} & {2} & {1}\end{array}\right]-\left[\begin{array}{rrr}{2} & {-2} & {-1} \\ {-1} & {2} & {2}\end{array}\right] = {?} } $
Explanation: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rrr}{-1}-{2} & {2}-{-2} & {3}-{-1} \\ {-1}-{-1} & {2}-{2} & {1}-{2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-3} & {4} & {4} \\ {0} & {0} & {-1}\end{array}\right]}$